The present invention relates to a method of and a structure for fixing a flexible electrical conductor, in which a plurality of electrical conductors are covered with a resin-made cladding member, to a fixing portion for connection to another circuit.
FIGS. 1 and 2 respectively show connecting portions 1 and 3 of flat electric wires (flexible electrical conductors) disclosed in Japanese Utility Model Application Laid-Open No. 30723/1991, as well as a flexible electrical conductor 5 connected to the connecting portion 1 or 3.
In the connecting portion 1 shown in FIG. 1, a step portion 7 is formed at a distal end portion, and connecting terminals 9 are exposed on this step portion 7. A pair of positioning holes 11 are formed at a distal end portion of the step portion 7. Meanwhile, the flexible electrical conductor 5 connected to this connecting portion 1 is covered with a cladding member 15 in which distal end portions of three flat conductors 13 are exposed. A pair of through holes 17 are formed in an end portion of the cladding member 15. A pair of fixing pins 21 of a fixing cover 19 are inserted in the through holes 17.
In a case where the flat conductors 13 of the flexible electrical conductor 5 are connected to the connecting terminals 9, the flexible electrical conductor 5 is placed on the step portion 7, and after the flat conductors 13 are superposed on the connecting terminals 9, the fixing pins 21 of the fixing cover 19 are inserted into the through holes 17 and the positioning holes 11. Next, distal end portions of the fixing pins 21 which passed through the positioning holes 11 and projected to the reverse side are caulked by heating. Consequently, the flexible electrical conductor 5 is nipped by the fixing cover 19 and the step portion 7, thereby allowing the flat conductors 13 to be electrically connected to the connecting terminals 9.
On the other hand, in the connecting portion 3 shown in FIG. 2, a pair of fixing pins 23 are provided projectingly on a distal end portion of the step portion 7. When the flexible electrical conductor 5 is placed on the step portion 7, the fixing pins 23 are inserted into the through holes 17, and after a fixing cover 25 is placed on top of the flexible electrical conductor 5, the fixing pins 23 are inserted into a pair of positioning pins 27 in the fixing cover 25. Next, distal end portions of the fixing pins 23 which projected from the positioning holes 27 of the fixing cover 25 are caulked by heating. Consequently, the flexible electrical conductor 5 is nipped by the fixing cover 25 and the step portion 7, thereby allowing the flat conductors 13 to be electrically connected to the connecting terminals 9.
In the case where the flexible electrical conductor 5 is connected to the aforementioned connecting portion 1 or 3, the cladding member 15 is nipped by the fixing cover 19 or 15 and the step portion 7 in which the longitudinal offset is prevented by the fixing pins 21 or 23, and the flat conductors 13 are electrically connected to the connecting terminals 9.
In the connecting portion 1 or 3, the positioning of the flat conductors 13 and the connecting conductors is effected by inserting the fixing pins 21 or 23 into the through holes 17.
However, there is a problem in that, in the aforementioned connecting portion 1 or 3, if the caulked portions of the fixing pins 21 or 23 become loose, play occurs between the fixing cover 19 or 25 and the step portion 7, and the state of close contact deteriorates, with the result that the electrical reliability in the connection declines.
In addition, if a force moving in the axial direction away from the connecting portion 1 or 3 is applied to the flexible electrical conductor 5, that force is concentrated on the fixing pins 21 or 23, the force is applied locally to the cladding member 15. For this reason, there is a possibility that the cladding member breaks. Further, if the force moving in the axial direction away from the connecting portion 1 or 3 is applied, the force is applied directly to the connecting portion 1 or 3, so that there is a possibility that the flat conductors 13 and the connecting terminals 9 may offset from each other. As a result, the reliability in electrical connection declines.
Furthermore, there is a problem in that when the flexible electrical conductor 5 is connected to the connecting portion 1 or 3, the fixing cover 19 or 25 is required, so that the number of component parts used increases, resulting in higher cost.